Bad software has bricked some Mustang Mach-E EVs

There's an adage among car folks that you never buy the first year of a completely new vehicle model. The thought process is that it takes at least a model year for automakers to work out any major kinks in an entirely new vehicle. While we aren't sure that's always true, Ford is having a problem with some Mustang Mach-E electric vehicles in the hands of owners around the country.

Some Mach-E owners have reported that the electric SUVs won't start even if the battery pack is full. Reports indicate a problem with some early versions of the EV has to do with how the smaller 12-volt battery inside the vehicle is charged. The Mach-E has a smaller 12-volt lead-acid battery that gets popped up by grabbing small amounts of power from the larger lithium-ion battery pack that propels the vehicle.

The issue reportedly has to do with the 12-volt battery failing to charge when the EV is plugged in to charge the main battery. This charging issue is a particular problem for those who live in cold-weather areas. Ford has encouraged users to leave their Mach-E plugged in to grab power from the grid during warm-up in cold-weather areas.

Mach-E's 12-volt battery powers multiple systems in the vehicle, and if it dies, the vehicle can't be started. When the issue arises, owners say that the FordPass app reports the vehicle is in "deep sleep" mode. Ford has confirmed the issue in a technical service bulletin filed with the National Highway Traffic Safety Administration that says the issue has to do with software in the powertrain control module.

The technical service bulletin says the issue impacts Mach-E SUVs built on or before February 3 of this year. Ford hasn't confirmed how many of its electric vehicles are affected, only stating a "small number" of almost 7000 units delivered in the first quarter of 2021 have the issue. Unfortunately, the software issued can't be remedied with an over-the-air patch, and the vehicles will be required to go to the dealership for repair.